HISTORIC SITES   The following are some of the historic sites associated with the Cromwellian conquest of Ireland:   Dublin Castle Cromwell established his headquarters here on his arrival in Ireland in August 1649.   Millmount Museum and Martello Tower Drogheda, Co. Louth. Scene of the killing of Sir Arthur Aston, Governor of Drogheda by Parliamentarian troops during the Siege of Drogheda on September 11 1649. The entire garrison of over 3,000 was massacred along with many inhabitants.   Duncannon Fort Co. Wexford. The New Model Army met its first serious setback in November 1649 when it failed to take Duncannon Fort, which was defended by Ulster Catholic troops.   Ormond Castle Carrick-on-Suir, Co. Tipperary. This was the home of James Butler, 1st Marquis of Ormond, leader of the Royalist coalition that opposed Cromwell. It was captured by the Parliamentarian Colonel Michael Jones in November 1649.   Kilkenny Castle Kilkenny was the first town to show serious resistance to Cromwell. His troops captured it in March 1650 with the loss of 100 men.   Clonmel Cromwell besieged Clonmel in May 1650, but fell foul of a trap devised by the garrison's commander Hugh Dubh O'Neill. Some 2,000 Parliamentarian troops were killed by the defenders. Sections of the old town walls can be seen in St. Mary's churchyard.   King John's Castle Limerick was defended by Hugh Dubh O'Neill against the Parliamentarian army under Cromwell's son-in-law, Henry Ireton, in 1651. It eventually surrendered in October 1651.   Back to Cromwell in Ireland